Tom Steyer, a billionaire retired hedge-fund investor, is aiming to spend $100 million to make climate change a priority issue in this year's midterm elections.

As the New York Times reported Tuesday, the Democrat is working to raise $50 million from donors to add to $50 million of his own money to bankroll his San Francisco-based political organization, NextGen Climate Action.

According to the Times, the money will be used for attack ads during the election, including the Florida governor's race and the Iowa Senate race.

For more on Steyer, check out Peter Overby's November story about the billionaire's 2013 Election Day impact in Virginia, where he and former New York City Mayor Michael Bloomberg spent more than $2 million each to help elect Democrat Terry McAuliffe as governor.

Overby reported:

Tom Steyer made his fortune as a hedge-fund manager. But in the past few years, he's started funding issue campaigns against the Keystone XL pipeline, and for action on global warming. In Virginia this year, that meant trying to defeat McAuliffe's Republican opponent, Virginia Attorney General Ken Cuccinelli...

If Cuccinelli was hoping for one or two deep-pocketed conservatives to match Steyer and Bloomberg, he was out of luck. No other Super PAC in the race spent even half as much as either of these liberals did.